SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a90cfc0d345ed20e106ebe5ed92a85428312e8ee8d472ac7b536600d5843355' 
  AND token = '7Yb9eTpfBmkLrB+Kv1mEYnHeRRqWZOurAW5q3SdjWHI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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