SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'bfd67dfd7fd6fa05221053800189fb7d07c60c564f4c434a7bf4b5a3a8452186' 
  AND token = 'JooR1387Ahgb/UQdf5+SiVMxvnE9Lj3oWw+p/siDY98=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}