SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '63cfdb20cee5aa41fef0b20223cb2d1c7059e256496eb137d1e91c332054deb8' 
  AND token = '68zWj6uzdjHoUueyLDKsZhD2PmsNN8FCR5MUHB/HuCc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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