SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '58bac1cf5622b114c4dadc4a17f64ef23da9cdf3bd3906342da927196878336c' 
  AND token = 'HC6oKM/BDn9B67wNkWRFrZt95KGCgxusiL/lkhNbTSI=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00024

JSON explain

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