SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '9778a4e1c76b7fe90e8346e0d57ddaf566b1f122d9fdd8c63cdf4ff2febcccde' 
  AND token = 'zZ/oadB7j2zsrZa4RYX3wrY62A6VeUipxzGXbQZFd3Q=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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