SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c1f5ec1ad61dae5688e91e4a23c5d2ec507bca89d883512dbb8c20c3689d193c' 
  AND token = 'HoH6UFc8wKFlSk1QC8XbbAvEc0sgvs6t/h2qZwTv2DQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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