SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '77a0ad0438ef67696159426491dd15bf3057bd0a4475b71e62b2b69807f15060' 
  AND token = 'zFbTRfcc25BANwaUpn8eLVu4iOO/GD/SdsT+iF7cCvA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00058

JSON explain

{
  "query_block": {
    "select_id": 1,
    "table": {
      "message": "Impossible WHERE noticed after reading const tables"
    }
  }
}