SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4c0f99bbb3bc6f53f7222ded6f6daed67102a8a3728b9fc3130b178913ba351' 
  AND token = '3i4VlsWt9Zoox/XxghPCL6mOlTwSygJqoRXDK3BtoaI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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