SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f576c17f431a6c5400032ac2c2a11fcf25fb42668ae641b0156ebae3c635fb07' 
  AND token = '1UtlxbWVBU3eLGteYvXt58nJwTeI8YvB83JhP5w/XJs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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