SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77ca94ad62dd8dc494e3370d85bdcf8fb669f6815f8c9001814053c52bb6385f' 
  AND token = 'bo9cfjLfHBnFoKuoUfVdbUG5CV3H1qfiqoxSMpjpeXM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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