SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '34ebbebbf15603e954e983ddcc3620a2c11c7c923769c931b8e42851f2501032' 
  AND token = 'u8xYUPDBZ8IFYOZHvyb9Qmm8PlOsMJiEjtBqLo3lh7A=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00019

JSON explain

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