SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '3e9b6b6ba9826e016aaa076ab1e916cd86c49ad17539f14ecc655d51977c6ffd' 
  AND token = 'MWxkJYDYmbV+j3Zt8mjrtM0JCtMoTpXwMCDwPHBhBBk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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