SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'e10f1cef8af56981df61553152d47aea2cca2795985ddf9c5b8cc4842a350bc6' 
  AND token = 'T5opGftGrjsW/ZcO9ZvtISd30GzVcP8ea0ApedoWHFg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00026

JSON explain

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