SELECT 
  1 
FROM 
  cscart_june_setuplock_keys 
WHERE 
  key_id = 'b98a7d4fb9b8676a0760c8c6df3c4822d64cdd17c9b3438114622bf11c30dddf' 
  AND token = 'vOCJSL4ciP5yYrkWNpHRMVMCuoVDxGZtD5/K/pH3gPA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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