SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b48a120854d85fa04a3e6b3363602a395674c599904d17f9a943570511895250' 
  AND token = 'aiYtnPbYOoonpcqHEAsFBZtsJSbCCfZrMr+TE55o0mw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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