SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '678487acddc0b60ae3d72a54128f31f5afce2933ea401973bbf610a99c437b1f' 
  AND token = 'gIB/1Wffrl+eKFFRNMEoYEShXL/VnDhD9jpduchP7R0=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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