SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '49b814ad48064628ba75cd83fa3a8c07358e694f5d52a8f36f2876257fb373b6' 
  AND token = 'TuF782WhRclwYjKMTd7NY0V/JzAwtJ7LJhkwrBPJxGU=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00028

JSON explain

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