SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '84b446d054870ea058d0cdae385ace4dd27d75db9aa1225a7224e5eb0268dced' 
  AND token = '2mgZsp0Jpc0huGZE0CS9fUIvnSdx5rebMDm/5Ezi/PY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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