SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4b2824d443f4c9edd863f7516069f29766148972962a54940e87a6ae043c405' 
  AND token = 'ouhLSsfoX85G+H2HFtz81+xVFXMcLM5jl0qLpG2Vgug=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00032

JSON explain

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