SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '576e86926107d1b4c2fadf32c3ab24b10a0d122ecc009d6bc9cf564598a53d9c' 
  AND token = 'CLvu3MLNWQQsxiEV3qUbxck5plHI15jk68sQ3fPd298=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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