SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'cb1a9f8f87a6e5342913e1e1ce48ffd1f962984afdc7b50932f1f7161dba723b' 
  AND token = 'jjp1mT+czuwjUSqUhU8TMv/HDEmG1D3QiXgO3e+w6ys=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00033

JSON explain

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