SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '62a9ceac3f899ddb7b3553010eee825a0982ed3e4503262bf2f8fdadbb0a1d57' 
  AND token = 'tgXrd+dtjfM+3hSviZ0hqYEDzw7l/ly2Tquuh3gw2O8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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