SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b3d42295fb5bb86050ad7db04385a54bf75457ded4995a82d8289cba98d8ba3a' 
  AND token = 'pXkOSZ+uj90kaDHG5lym8XpEODd5rhkZYCBOoM7r3Jc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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