SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '7126ec8b88600a010120866d48ca7a7147f9d2b900e250117879b7b9834a6c33' 
  AND token = 'LYlH3ECbzq31Q9feH3GRoveZNc8U8HMhcVPI5LM3vQQ=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00037

JSON explain

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