SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7b47350edfa52c4e2c7ecf38a3747ff22931ce743f452956d0674b1fbef7883a' 
  AND token = 'T3LHywbZT9uLPdjDddrKvbO0UQ4sjdvDxDkCpjZqpnE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00036

JSON explain

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