SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a396699e65ba896baaf80b8768b2b10884a508e84d30d334a38c3d3a6d6f44b6' 
  AND token = 'VhQ6BMgEYzUdWlTB2VJTaFU/g++ohL8ZwIkm/f9D+QY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00030

JSON explain

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