SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c53f002791b14ae514ba692669fc9f3112af63dfbf49013269a415bacb09809' 
  AND token = 'KVgJr8gLPGT4yAZfwZFG3litfmlU/K0A/DCSneFkEa8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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