SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '6a5542e7da939b716f34964a52f2ad239407cb9e86c382f065a3d5ecd53d1291' 
  AND token = 's59p8JotMPzBGuQwtgOAcLGXFCucpqLa+GR+zL/7OOs=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00016

JSON explain

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