SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6f04882b76b4979375fd962c5a1c5246810d7e202a2c846f7d0620517fe5bd28' 
  AND token = 'ZQ8Es2HOW0jbpu6O2kvMiX0mX0eHN/1WZWYKvRCCyMQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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