SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = '8a3884fe1322ed2e6fa0a03b9c13af607140c40e4ae77c365a783663177786ce' 
  AND token = '7nnO/GlaQzop9RjD1pMLtSWALdQN7zOuP6QxBEeMTDY=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00035

JSON explain

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