SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2f4b888ffcde10b3386eaed1bbeea73559449f52f2dceb1de9c8d1688c47b0a3' 
  AND token = 'wdaTKdC4DCZvEJ/yMKht0Vzud8ot07eB0JksXqc0qlM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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