SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f2b9ec860d2e3564361b7dd71a69cff03252f3f8f6d9a30633acd33ed441a5ac' 
  AND token = 'SOYcqiSHIg2Yr2tdInMnlPZtOF+L7Fs8ijmVoOJle+0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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