SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '387cf12bb4a2ccbf4614b1a2f0773fd7be504195e1641816cb4f61c8f8dae7b0' 
  AND token = 'vs7zNGiHaS/FfQDdl5eV337lYVccJtiKWIljxxEPeEM=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00059

JSON explain

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