SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'a0fa40dab5d0963652c92db59f702951276f79149045e16112aace23306245a5' 
  AND token = 'vrQaiixZkvA3EIm0isWH0ri6XrbiSsb35eQcTuF4KKY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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