SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '70eb38ffce8f6128c4091f7344d4d1c6cd634234a92e408bebc8be1da1ea40c0' 
  AND token = '9LfyHxxzYEH860O7MxU2EQZOqj0ajDG1U1PqYykSEjE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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