SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e571f0afa5a91b9b487b28205ba30e465c5b43edff95c65923286f50e985e281' 
  AND token = 'A2afgAVUTKxd6kTwPz5smOlUD1VBFqT10VCCeOJvTMU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

{
  "query_block": {
    "select_id": 1,
    "message": "no matching row in const table"
  }
}