SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '82d76a9729dfe68a9750a39962de6932e187fa74cc50ec006652074b27623a46' 
  AND token = 'EmRI1KsCYT/keD0i7C9LR152POlvj5ZMxPrQXxHRnic=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00057

JSON explain

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