SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7abdfec8af96ebd29d6dec20a090e14875ec4fd80d656049843aa1bfcd1ec5a0' 
  AND token = 'HF+YW9y2eUkMv2WnjA1HRmbtfJrSqjvI92+o7CIbepg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00042

JSON explain

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