SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'f4f55698e0c141bde93727fea8f4942df46903e006c0deec3459944d376c3978' 
  AND token = 'EfxCFSfZyG/DgKq7fRpN/1+lIddkwESJfCxOezaMJvY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00044

JSON explain

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