SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b14f5e3e6f6adc5b766b2753c1d9bed5d4bfc1bbb99573a2f06378b51c5966e0' 
  AND token = '+PNuTD/M99amch9FVBqkbpNl6rRGa7+6kYmsc5+2x9k=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00022

JSON explain

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