SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '805946c46d88b339436875134c8391c001e22b107c871746fb984db5c5a8e3e6' 
  AND token = 'xE0uMOLEIuytj19AYrt1ENZwtfPFDjVxrqiNE/1iPfI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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