SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7fa42f68662475086d3c1d40af3acb654795eca5360b2115ba597a1ca6fe4b3b' 
  AND token = 'a6vXuAyRhgzH4w5B8chn7HQeVDA25iWI2Muworf4LsQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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