SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '378c2e2ed10d1944a44d1e25ea96719a1cd5c93c867f233aed16a93a26099a74' 
  AND token = 'MTiB9L2CL5NveS67f7txbQQVbwdqY2fBJknwJuXvZ10=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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