SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '241276df23c9f36f91dcc8c452603d689f099d88a691272f308486e8cea94e78' 
  AND token = '5Fw7P9hRz9+LwmFfbIrq4NIYD+DLCNV/5YmcbVl32gs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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