SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '78f35c4bd60089a523ae563dcb708dc874a590238a8e2b9c68a3d081151be3dc' 
  AND token = 'zBplZx3FzdUjtJM9s+b7LUVqxxACUr/doagofGT7LLg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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