SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '3a7e675516e5b8e76db33811f068728e848da9a144835eceadb62a38087a0de1' 
  AND token = 'gGj+pdvpzgXugZR1USUB9n38tfU2kOUhO4dnP2+tUvc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}