SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '275cbc2820abcc813bfaf1d3e45337a8426302451c13b0c6bad4d2a181229172' 
  AND token = 'oReyUGlIoiMungfGS3oLH2LfqphLmRgI6sruisiE9fg=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00039

JSON explain

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