SELECT 
  1 
FROM 
  cscart_aprillock_keys 
WHERE 
  key_id = '355c6be84d08637b6d68962981ce0861551141a5b3ae2732e0bfc997aa58ebe2' 
  AND token = 'fv9pZikFVm5UiCZzjt85ODWPDh3HCUZkfUlixMVUm8c=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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