SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2de780e1e56cae963f04f8c876fd3e577b2363acf2a8c4fe0f2036447d6a555a' 
  AND token = 'IvZtaKQ68v81CcRC8+RXhVHBujlfPsFLNIDKbCYxIbg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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