SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '05a8a39abc847595f8594392c4c165965ea4e1a2478b4eeffb3ae841e9b48127' 
  AND token = 'm/pogCg4PNPYfMMezRpm/NLfp2xyMIsEjOZR+yMpGh8=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00018

JSON explain

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