SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7a452b1aca7c5b5110c0d0b52fd2da5cb7755d8a9bf29120cab3d2e72dc626d7' 
  AND token = 'UEwC+LrEhdFGQKdtpEnsrmGJWyn5snX7Wx89/W3uje4=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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