SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6dbdde84e1d6c418cec96bdaf7d303205baedb25852ad970bf7824b5295d85b6' 
  AND token = 'sRaj+BHd5j5bs2/FaTyLTFk6Iwq4MCzlGK7EMpwHPeE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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