SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2c40c7bc54ff88b4057ab919d4523a6e25c2db86cfb5f6c46ef45d6d1dde8695' 
  AND token = '1uALGRk0jVi6itRnQxVEdMsiOwaupTfR4P3puNU/Oxo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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