SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb5a2f6c57d4b326e2ebf5f4636b66d1cb7f3c7a445817d3ac439b6434136720' 
  AND token = 'OyVDZJA2sY9OlXojGA1EH1SxcuAqIzbxtNZ4BHb3bGA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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