SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '0d67d3892583e00121caa1c4c6cc8915b6640d18439d6930691e5498baa7ea35' 
  AND token = 'qg08lhyvEh5BHIRw5nMiETCIfOHVqtQy+CwakvPdTPc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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