SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '891a48297c22e292db49cb3c191eb74482ee3deed9c31eaf1e2a5205a74cdb88' 
  AND token = 'DwvSMJLhkD6AP7VvgU7VQmYReR1EPsKUEXcRXFiUz4s=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00054

JSON explain

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