SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '38e75e5a73e6c60135ee28d338f194f60045f50911d4ab5a7702b68fb67ea4d4' 
  AND token = 'VlKdipXhVfNJ/mTeizddgpdcCRTp+U2rvjSwRFc2js8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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