SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '61a997771538f26793a74e02da258fc51b0af3e7d468867f4d020f5a4fc4f430' 
  AND token = 'ecDQfEgakaRVPOQpjmp7RwD2csaNXuKkdrKEaHRJm5M=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00025

JSON explain

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