SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '018e37f39cfc52b4a62cbfdba43b8800ed394c5a83174549622429c63a132415' 
  AND token = 'T8rjUwCC7OClmv72Y3n58hSbXS6uMQzUXpXX2VJQw+w=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00012

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}