SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = 'e589b908629ffaaf1008aaec3630e9dd00526dd0e44f835164d16db3f1fb1b79' 
  AND token = 'mDgnjb+i6LJROlTamk/fNOMcdRFLRaGNEpRxPASDmEo=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00034

JSON explain

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