SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '989c83407a568c4110ab6119a14eae31472efee2416a01ccc6bee2f6e127f667' 
  AND token = '1sdR55slR4EeLHy9uflxwAbsIRx1mbmKmbedgjZq3Bc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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