SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'fe36f724b1e23b15559d41ed879685b59152a47f331a8b095282043961083eb6' 
  AND token = 'rsaJlkM6nv9WXBNkHB2NPuy+q6HLYlxAvJBq24VgA5Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}