SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'eece4fd3d4f8100adb3e6662a757562d129fe2ec59785da41e09ec57d465cad8' 
  AND token = 'qQscsdIA7sJjupq6m7j89JkudIiKk9HbC1pIfit+dbg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00068

JSON explain

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