SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ae707656abc4bdff5ca65ecf4721df68f0987b0842c3b5548b4f79ea3a2080d7' 
  AND token = 'dmtuKpTPWhN5vaiRghQCigLUw3+LnTWuVaUAA7vhuTg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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