SELECT 
  1 
FROM 
  cscart_lock_keys 
WHERE 
  key_id = 'c96dafd18d4b550616c73d86afd66277af82d59f9eb23c771a252e44f4908ccb' 
  AND token = 'b6oerg0dmgwEH0n9XRzYBnjEmSSDtIMig21yOVYLDAA=' 
  AND expiry_at > UNIX_TIMESTAMP(NOW())

Query time 0.00041

JSON explain

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