SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'd651ce9f446e7f293ee0a819a0535bd5a02f9692e7c23a8275cf0be1b2f1df78' 
  AND token = 'jyP1eLe8DsG7wUmgDNg7Fot+3F//LlqrNk8KBCi7K0s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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