SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '5a92d7a07a2c7beda0e858b2d708cf14546690a8bcff5cee7fd4263d563e282d' 
  AND token = 'UMHXcbCcYADU96DIfDYyshxlfEpBkZyaWr2e8va02Zc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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