SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '2b0e0a54e964937f2321ed73e003fba396d28c5b2afdc13a35520b0d6cd00925' 
  AND token = 'okC7dCxgnUsVSswV+Ub4jCg+kZSCqrE65XAGpWM9Whk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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