SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '23f03bae2542a26d6181c8fc7aaa45a6508e7bb019bf6f6a3c8a53f8ab0f85d0' 
  AND token = 'Fi4Y48u6NFMxwH52MmohLEgfgk77NvY/o/JnCjCXpqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00038

JSON explain

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