SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '20337cc58ba1baca4135fc0390ffeba0c3b424d380b455869741ded3482eafaf' 
  AND token = 'HSQN91MLBUZNjvMh3osKAXfJM5cbsk6rj/vVFATreqQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00029

JSON explain

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