SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'ad58d1a3a1375d57d5eed00fce40975f28b94c2188df328b46470a658ebf4c89' 
  AND token = '3VXX6rJBrdMt4UA4au2eNdFGkT+GP/afdIMSy6RdHZw=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00020

JSON explain

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