SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '828ce219cd014ee7b87f4fb44281f4fbac47ea0a6d973c7c8f8411d7623d3f4f' 
  AND token = 'njnmWZww6yj06XiRTMTgKloQtrV3anu+VnOoatZNBXc=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00023

JSON explain

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