SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '55357b0a86213a871870b3cd65df5a4d3e1c9e02c930cc158f340f1b6496825f' 
  AND token = 'CHeumpAFxvFAgoj+z0LL17hQE/3/J9r+JFXp1zkT0aE=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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