SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '192dcbd4150232a490b5842ffea64e6adbb4b18046771590f58735650213e743' 
  AND token = '3lwWFo7rLSB4wNZ4stI22WpeITRdImFHsABwMyCSjUo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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