SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2a656cfcf63623353381aa57b6d413a34d46187a01ca10db4f1b6f368dba46d4' 
  AND token = '39INeHazBCK4HFxgS1zCQwvIwXKwt4fQS9QD9DAAm2Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00027

JSON explain

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