SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6089be68258bad98ced8fb98c62587930e4d672709c31e4f8d3696afbe501f4d' 
  AND token = 'k4q6rsB6kV1Nk/mhf9zDptlOyVTZUvfZQ/Eurxqc6cc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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