SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '1f189cad4c6804d600d4fa18561d687401e5978631d48df6157a1898dbf02691' 
  AND token = '2r+/pl1fOE7/vOzpHcAouXPPwYCIGqOTtJf5q5+l/rI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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