SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'a5a0ddba472666c44bf161e96001fab6059c2a5bf71b2ac04aa3c44a66dc0897' 
  AND token = 'DzC7bo7/pQivj4UxMifNqDAq1QnctzQlAj0WqOtjQGk=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00053

JSON explain

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