SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'b351a8da2b49bf955c14e459c1de6ccd5428be1c19d03f0d0cb9a447f3f98abf' 
  AND token = 'ZwtFUtv5ogEgVWRMF27zMab0Ckts9ARMe0pGBot6hhI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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