SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e4b3489d386ee3cb15cdcb1313a93eed899d82366f3989783505bd7d764d3e7b' 
  AND token = 'j/3qOoKl/jFt2GplG/FBq8QP4Xn8DJ4nKVGufcwFEYg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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