SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7923abbaace2f053a3ff9d89bb813246b0ce41e060f27b9783b382f9092f0e3a' 
  AND token = 'tx/aQkkgCekpP5q76v85TpbGgPZMWMjpOsVwKYbr51E=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00021

JSON explain

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