SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '805f00d405548cff307052a8be52445d6bcae3e91a7437505f9f4050189a89c0' 
  AND token = 'KvX2JKKDIpWKsZXpXaLQhqxQVlnGSjxsPgI7gjqholI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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