SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '31fca4379eecf7a9f49dd05279fc056b8f033a1b4766736640c8a71cde82b86c' 
  AND token = 'veH5OXDp5oqVSBasA2rMlIcl0YEXvfTV2hTOipMG8qg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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